If you follow this easy guide correctly, it should take less than 20 minutes to get all your screenshots into your thread (under 5 minutes if you have already taken pictures of your map). If you have already taken pictures of your map, you can skip to step 5: Start a game for the map you want to show. After starting it, end the game. Go into theater mode and start the game. Pause it and take pictures (Press "X" and select the camera icon). Go on the internet to your service record (on Bungie.net) and take a look at your recent pictures. Click on "View in High Res" for the ones you want to use, and download them to your computer. Upload them to a photo site, like TinyPic.com. Highlight the link under "IMG Code for Forums & Message Boards" (for Tinypic) and post it on the thread. Your pictures should come up large and in high quality. Enjoy!
I appreciate your trying to help, but I think most people know this, and if not I'm not sure if this should be in the Forge Discussion.
It's also a lot easier just taking the pictures and going to haloscreenshots.net and direct linking from there.
There are no other places to put this, which is why the admin(s) should make one. And no, you are wrong, I constantly see people who either have broken screen shots or no screen shots at all because there is no guide on how to post them.